Cooking oven and heat control therefor



Dec. l0, 1940. w. H. slcKlNGER COOKING OVEN AND HEAT CONTROL THEREFORFiled March 2, 1938 Planted Der.. 1o, 1940 luNrrrm STAT COOKING OVEN ANDTHERE HEAT CONTROL FOR William H. Sickinger, Chicago, Ill., assignor toCrown Stove Works, Cicero, Ill., a corporation y minou Appunti@ Maren z,193s, serial No. 193,386

2 Claims.

This .invention relates to the .art of cooking stoves Yand ranges, andmore particularly to oven structures. In the evolution of modern stovesand ranges, particularly those of the electric type,

a comparatively recent new feature has been developed consisting in whatis known in the trade as a thrift oven. This consists of a small cookingchamber or oven that is located directly over the main oven of the stoveand takes the form of a sort of well, usually of circularcross-section.. that opens through the top plate of the stove and isequipped with a heater at its bottom.

Suspended within this chamber or well is a portable cooking vessel inthe general form of a pail or bucket of suiilciently less externaldiameter than the internal -diameter of the chamber to provide a narrowannular space surrounding the vessel that isillled by the hot air andgases rising from the heater. In this cooking vessel may be placed smallroasts, stews, soups and other articles of food that can be cookedtherein in less time and with a less expenditure of heat than if theywere cooked in the large main oven or over the usual burners in the topplate of the stove. From this fact it derives its apt name of thriftoven.

One purpose or object of this invention has been to render an auxiliaryor "thrift oven of this character more reliable and useful forperforming its intended function by equipping it with an improved devicefor automatically interruptingthe further supply of heat when a maximumpredetermined heat has been reached vin the cooking chamber.

Another object has been to provide in association with such anauxiliaryor thrift oven an improved manually operable means by which theheatregulator can be adjusted to interrupt the supply of heat at varioustemperatures according to the maximum degree of heat that may be used tocook any given article of food without danger of scorching or burning.

An illustrative embodiment of the invention is shown in the accompanyingdrawing, in which- Figure 1 is a vertical section of an upper rcoritscooking vessel in axial vertical section thereln, and the heat controldevice in side ele- 50 vation. l

Fig. 2 -is an enlarged fragmentary vertical sec- 4tion through the upperportion of the cooking chamber, showing a device for securing thereto aring that supports and centers the cooking ves- 55 sel in the cookingchamber.

(o1. zia-ss) Fig; 3 is a perspective detail of the supporting andcentering ring above referred to. l Fig. 4 is a vertical section throughthe rear section of the heat control device shown in Fig. l, showing theheater circuit switch and its ad- 5 justing means. y

In the drawing there is shown at I0 an upper rear corner fragment of astove structure, wherein is located directly over the main oven,indicated at I I, an auxiliary or so-called thrift oven 10 designatedgenerally by I2. The cooking chamber of this thrift oven takes thegeneral form of a well I3 formed by heat insulated side and bottom wallsand opening through the top plate Il of the stove. The side wallspreferably and as 15 shown comprise inner and outer sheet metal liningsIB and I3 with a filling of rock wool, asbestos, or other similarinsulation I 1; and the bottom wall is similarly constructed comprisinginner and outer sheet metal linings I3 and I9 respectively 20 with afilling of the same insulating material. Mounted in the bottom of theoven I3 is an electric heater 2l supported on the bottom wall by feet 22that are preferably attached, as by screws 23, to the inner' lining'IIl.Circuit lines 2Land 25 25 from a source of current lead into the heater2l, as shown.

28 designates a cooking vesselhavlng the gen- ,eral form of an ordinarybucket or pail, and of a height and diameter suillciently less than the30 n internal height and diameter of the chamber I3 to provide a space21 between its bottom and the heater 2I and a narrow annular space 2Bbetween the'opposed side walls of the vessel and chamber 'i ner portionof a stove. showing the thrift oven and communicating with the 'space21. This 35 cooking vessel 26 is obviously readily insertible andremovable through the open top of the cooking chamber I3. The cookingvessel 23 is preferably suspended in the cooking chamber by aconstruction which both centers the vessel in the chamber and alsoprovides a heat seal for the upper endv of the heating space 28. Tothese ends, I provide a ring designated as a Whole by 29 of the formshown in perspective in Fig. 3 and in cross-section in Fig. 2, this ringcomprising an intermediate horizontal web 30, an internai dependingflange 3l, and an external upstanding flange 32. 'I'he web 30 is formedwith holes 33 for the passage of bolts 3l by which it is secured,through the stove top plate I4 'to 50 underlying angle brackets 35 spotwelded to the inner wall lining I5. The inner flange 3l fits within theupper end of the chamber I3 thus f centering the ring 2l, which latteris preferably sput, as shown at 2s' 1n Fig. a to accommodate 55.

small'variations in the diameter of the inner `lining I of the cookingchamber.

.The upper end of the cooking vessel 26 is formed with a counter-sunkseat 3B for lan insulated cover 31, andwith an outwardly extending rim3B that rests onl the' top edge of the ringwange 32, and a dependingflange 39 that nts over and around the upstanding` ange 32 of the ring29.v The engagement of the rim Il with the top edge of the ange 32 forms'a heat seal for the space 2B, while the ilange 39 co-operates with theilange'32 to center thecooking vessel in the cooking chamber.

Turning now to an important feature of the invention which comprises theapplication of a heat control to the thrift chamber, 40 `designates asan entirety an automatic device!` that may be mounted on a rearinstrument board B of the stove, and includes a thermally opened switchin the circuit ofv the heater 2| that is operated by a heat responsivemember subjected to the mean temperature of the oven I3.

, The casing comprises iront and rear sections 4I and '42 separablyconnected by bolts 43. In the rear section 42 is mounted onra screw 44an insulating block 45 in which are secured a pair of spring switch arms48 and 41 carrying' nlled with a heat expansible liquid, such asmercury, the chamber of the head 48 beingin communication through acapillary tube 49 with a heat conducting tube also filled with the sameexpansible liquid. This tube 5|) is embedded in the insulation I1 and iscurved to partly embrace and lie in contact with the Iinner lining l5 ofthe cooking chamber. On the center of the head 48 is aprotuberance 5Iwhich bears on the inner vend of a stud 52 that is attached to `theswitch arm 45 and extends through a hole or slot 41"' Vin the yswitcharm 41. When the heat in the cooking chamber reaches a predeterminedmaximum, the contacts 48' and 41' are separated, and the circuit oi.'the heater is opened until the temperature falls to a point that allowsthe automatic` closing ofthe contacts 46', 41'.

This automatic heat control also includes a v simple device by which theoven temperature at which the switchv will be opened may be varied.

This consists oi' a threaded stud $3 screwed through a fixed nut 54 inthe inner wall ofthe casing 42 land carrying on its inner end a pin' Ilof insulating material bearing against the switch arm 41. By turning thestud 53 the set of the contact 41 relatively to that of the contact '45may be varied, so that the interruption of the heater circuit will occurat higher or lower oven temperatures.. To prevent easy or accidentalturning oi.' the adjusting'stud I3, the latter is equipped with a collarIl fast thereon and said-nena.

a thrust spring I1 between said collar and the nut 54. which createsfriction between the threads of the stud and the nut.

To the front face ot the instrument board B is secured an escutcheonring 38, in which is re-y movably mounted, as by a screw-threaded joint,

the holding ring 59 of a glass window 60' that covers the outer end ofthe stud 33.' Behind this window is a small signal lamp (not shown) thatmay be so connected to the main heater circuit as to either go on or oi!when the heater circuit is opened. This signal feature is old and formsno part of the present invention.

Erom the foregoing it will be seen 4that the Iapplication oi' thisautomatic 'heat control yto the thrifti oven of a stove or range Spellsa further economy in the use of such oven by providing an automaticdevice that prevents overcooking or burning oi' the food and thel wasteof heat involved therein.

Variations and modiiications of. the structural details may be resortedto within the scope oi the claims.

I claim:

1. Ina stove of the class described, the com,- bination with a stove topand an instrument board thereon, of an auxiliary oven having heatinsulated side and bottom walls having metal internal linings and openat its upper end through said lstove top, an 1electric heater mounted onthevbottom wall oflsaid oven, a

portable cooking vessel insertible and removable through the open top ofsaid oven', and an automatic heat control device, including a casingmounted on said instrument board, a pair of spring arms carryingnormally closed heater circuit contacts in said casing, -a hollowexpansible thermal head in said casing, a stud 0n one of said springarms in contact jwitli said head, a heat conducting tube in contactlwiththe side wall lining of said oven, a `capillary tube connectingsaid'heat conducting tube with said head, and a heat expansible liquidnlling said head and tubes.

2. In a stove or. the class described. the combination with a stove topand an imtrument board thereon, of an auxiliary oven having yheatinsulated side and bottom wallsfhaving metal internal linings and -openat its upper end through said stove top, an electric heater mounted onthe bottom'wall oi' said oven, a portable cooking vessel insertible andremovable through the open top oi' said oven, andan automatic I heatcontrol device, including a casing'mounted on said instrument'board, apair'oi spring arms carrying` normally closed heater circuit contacts insaid casing, a hollow expansible ther-vmalheadinsaidcasinlr,a'atudononeois'aid'l 'spring arms in contact withsaid head, a heat conducting tube in contact with the. side wall, tlining of said oven, a capillary ytube connecting said heat conductingtbe with said head, a heat expansible liquid nlling Bald head and tubes,and

manually operable means mounted in said casing for adjusting theposition of one oi' said spring arms whereby said contacts will beseparated under a greater or lesslexpanding movement of' 'wnmsirHQsIcxrNGnR.

